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2000 Models

WARNING: This page is about a different car, the 2001 Pontiac Bonneville and 2000 Pontiac Bonneville. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK  under TROUBLE SHOOTING and go to next step.
  2. Connect scan tool and turn ignition on. Use scan tool to perform RECALIBRATE ALL MOTORS in INSTRUMENT PANEL MODULE SPECIAL FUNCTIONS. If scan tool displays any DTCs, see DIAGNOSTIC TROUBLE CODE IDENTIFICATION  table under SELF-DIAGNOSTICS. If no DTCs were displayed, go to next step.
    3. NOTE: Ambient (outside) temperature must be 60°F (16°C) or higher.
  3. Cover sunload sensor. Start engine. Fully open all panel outlets. Adjust driver's side temperature to 60°F (16°C). Depress MODE button and select PANEL mode. Set blower speed to maximum. Turn off passenger HVAC control. If A/C compressor operates, go to next step. If A/C compressor does not engage, see A/C COMPRESSOR CLUTCH CONTROLS - ALL MODELS article.
  4. Run blower and see if it provides sufficient airflow. If sufficient airflow exists, go to next step. If sufficient airflow does not exist, see BLOWER MOTOR DOES NOT OPERATE PROPERLY  .
  5. Perform A/C system performance test. See A/C SYSTEM PERFORMANCE  under SYSTEM TESTS. If both high and low pressure readings are within specification, go to next step. If high and low pressure readings are not within specification, see MANUAL A/C HEATER SYSTEMS - TROUBLE SHOOTING article.
  6. Check right and left upper temperature sensors for proper installation. See AIR TEMPERATURE SENSORS  under REMOVAL & INSTALLATION. If a problem was found and corrected, go to step  22 . If no problem was found, go to next step.
  7. Start engine. Fully open all panel outlets. Adjust driver's side temperature to 75°F (24°C). Depress MODE button and select PANEL mode. Adjust blower speed so that 2 bars on fan speed display come on. Turn off passenger HVAC control. Place a 2" (5 cm) square piece of paper over sensor air inlet. If paper stays in place, go to next step. If paper does not stay in place, go to step  11 .
  8. Turn ignition off. Connect scan tool. Cover sunload sensor. Start engine. Adjust driver's side temperature to 75°F (24°C). Turn off passenger HVAC control. Using scan tool, observe RIGHT and LEFT SOLAR SENSOR DATA parameters. In INSTRUMENT PANEL MODULE OPEN/SHORT data list. If scan tool indicates that both RIGHT and LEFT SOLAR SENSOR parameters are more than 230 counts, go to next step. If scan tool indicates that both RIGHT and LEFT SOLAR SENSOR parameters are 230 counts or less, go to step  17 .
  9. Uncover sunload sensor. Direct a light source at right and then left side of sunload sensor. If counts change similarly and correspond to proper side of sunload sensor, go to next step. If counts do not change similarly and or do not correspond to proper side of sunload sensor, go to step  17 .
  10. Place a thermometer near right A/C outlet, left A/C outlet and inside right and left upper air temperature sensors. Using scan tool, observe RIGHT A/C DUCT TEMP, LEFT A/C DUCT TEMP and INSIDE AIR TEMP DATA parameters in INSTRUMENT PANEL MODULE HVAC SENSORS data list. If scan tool indicates sensor temperatures are near thermometer readings, and within 5°F (3°C) to -5°F (-3°C) of each other, go to step  12 . If scan tool indicates sensor temperatures are not near thermometer readings, and or are not within 5°F (3°C) to -5°F (-3°C) of each other, go to step  15 .
  11. Check for a blocked or disconnected aspiration hose. If hose was found disconnected or blocked and then repaired, go to step  22 .
  12. If customer needs to change temperature set frequently to maintain comfort, see SET TEMPERATURE REQUIRES FREQUENT ADJUSTMENT  . If customer does not need to change temperature set frequently to maintain comfort, go to next step.
  13. Start engine. Ensure all instrument panel outlets are open. If system operates properly, go to next step. If system does not operate properly, perform appropriate symptom test.
  14. Connect scan tool and turn ignition on. Use scan tool to adjust TEMPERATURE OFFSET in INSTRUMENT PANEL SPECIAL FUNCTION/SET options as needed and go to step  22 .
  15. Check for loose wires and poor connections at suspect temperature sensor harness connector. If wiring and connectors are okay, go to next step. If wiring and connectors are not okay, repair as needed and go to step  22 .
  16. Turn ignition off. Test suspect sensor resistance. See SENSOR RESISTANCE  table under A/C SYSTEM INSUFFICIENT COOLING. If resistance measures near specified value, go to step  18 . If resistance is not near specified value, go to step  20 .
  17. Check for loose wires and poor connections at sunload sensor harness connector. If wiring and connectors are okay, go to step  19 . If wiring and connectors are not okay, repair as needed and go to step  22 .
  18. Check for loose wires and poor connections at Instrument Panel Module (IPM) harness connector. If wiring and connectors are okay, go to step  21 . If wiring and connectors are not okay, repair as needed and go to step  22 .
  19. Replace sunload sensor. See SUNLOAD SENSOR  under REMOVAL & INSTALLATION. Go to step  22 .
  20. Replace appropriate temperature sensor. See AIR TEMPERATURE SENSORS  under REMOVAL & INSTALLATION.
  21. Replace Instrument Panel Module (IPM). See INSTRUMENT PANEL MODULE (IPM)  under REMOVAL & INSTALLATION.
  22. Operate system to verify proper operation. If system is not okay, go back to step  2 .
    SENSOR RESISTANCE

    Temperature - °F (°C) Outside Air Resistor - K/Ohms Inside Air Resistor - K/Ohms
    14 (-10) 5.27-5.98 15.42-16.89
    23 (-5) 4.03-4.52 11.76-12.80
    32 (0) 3.11-3.44 9.03-9.75
    41 (5) 2.43-2.66 7.00-7.53
    50 (10) 1.91-2.07 5.47-5.85
    59 (15) 1.51-1.62 4.31-4.58
    68 (20) 1.21-1.28 3.41-3.61
    77 (25) 0.97-1.02 2.72-2.86
    86 (30) 0.78-0.82 2.17-2.29
    95 (35) 0.63-0.67 1.74-1.85
    104 (40) 0.51-0.55 1.41-1.50
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